This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from my application FORMING METHOD OF VIA-HOLE IN INK-JET PRINT HEAD filed with the Korean Industrial Property Office on Jul. 27, 2000 and there duly assigned Ser. No. 43339/2000.
1. Technical Field
The present invention relates to a method for fabricating an ink-jet print head and, more particularly, to a method for forming a throughhole in an ink-jet print head.
2. Related Art
Methods for discharging ink in an ink-jet printer include use of an electro-thermal transducer (the so-called xe2x80x9cbubble-jet methodxe2x80x9d) for generating bubbles in ink and discharging the ink using a heat source. The electromechanical transducer discharges ink by varying the ink volume using piezoelectricity.
Such methods involve the use of an ink-jet print head having a throughhole formed in a substrate thereof for supplying ink through ink channels to ink chambers. Typically, such throughholes have been formed by spraying sand under high pressure and speed. However, such a technique has several significant disadvantages.
Specifically, such a technique is not suitable for mass production of the ink-jet heads. The sand spraying apparatus must be provided with a spray nozzle of highly-priced material and strong abrasion resistance. In addition, the throughhole openings formed by such a technique are often cracked or damaged in the fabrication or formation process. Finally, high-precision equipment is required in order to form a throughhole of precise size and positioning.
To solve the above problems, it is a first object of the present invention to provide a method for forming a throughhole in an ink-jet print head, wherein the time for forming the throughhole on an object to be processed is short, thus enabling mass production of the ink-jet print head.
It is a second object of the present invention to provide a method for forming a throughhole in an ink-jet print head, wherein the costs required for forming the throughhole are reduced and the unit price of the product is accordingly reduced.
It is a third object of the present invention to provide a method for forming a throughhole in an ink-jet print head, wherein damage to the edges of the throughhole on the opposite side of a processed surface due to shock imparted during formation of the throughhole and abnormal processing of the throughhole (that is, formation of curvature of the edges of the processed surface) can be efficiently suppressed.
It is a fourth object of the present invention to provide a method for forming a throughhole in an ink-jet print head, wherein the throughholes are formed with high precision and have a uniform size.
Accordingly, to achieve the above objects, there is provided a method for forming a throughhole in an ink-jet print head. The method includes the steps of forming a bubble-generator, including a heater, adjacent to a throughhole-forming region on one side of a substrate; forming a first mask layer for covering portions, excluding the throughhole-forming region on a first side of the substrate; forming a second mask layer for covering portions, excluding the throughhole-forming region, on a second side of the substrate; forming a first well having a predetermined depth on the throughhole-forming region of the substrate, and which is not covered by the first mask layer, by spraying sand under high pressure at a high speed onto the first side of the substrate; forming a second well corresponding to the first well on the throughhole-forming region of the substrate by spraying sand under high pressure at high speed onto the second side of the substrate with the second well not covered by the second mask; forming a throughhole by overlapping the first well and the second well on the throughhole-forming region; and removing the first and second mask layers.
The processes on the substrate are performed on one entire wafer at a time, the wafer having a plurality of substrates thereon. Also, the sand is sprayed under high pressure and at high speed onto each side of the wafer. Preferably, a region of the wafer at which the sand is sprayed, and on which the plurality of substrates is provided, is large enough to include a plurality of substrates. Since the region on which the sand is sprayed moves to each side of the wafer, it is possible for the sand spraying apparatus and the wafer to move relative to one another so that the sprayed region on the wafer may be moved as required.